Bags to be worn on the back (generally called backpacks) are usually carried by two straps extending over the wearer's shoulders which bear the load carried in the bags. Backpacks vary widely in form and size to suit the user's needs. For hiking and camping expeditions, trekking backpacks may include internal or external frames made of carbon fiber or aluminum, have capacities of 100 liters, include specialized features to distribute weight and compartmentalize items and weigh 8 pounds when empty. For transporting a few lightweight items, cinch sacks (which may also be referred to as drawstring backpacks) are designed with straps that double as drawstrings to control the opening at the top of the bag. This design allows for simplicity as these bags may require as little as a simple sack and two drawstrings resulting in backpacks with capacities of around 8 liters and weights of just a few ounces.
When backpacks are loaded with a significant amount of weight, the distribution of weight over the relatively thin straps with little contact surface area on the wearer's shoulders may cause physical discomfort to the wearer as the straps impress the weight over a concentrated area. If a wearer must carry the backpack for a significant period of time, this discomfort may become substantial. Accordingly, many backpacks include comfort features to combat this issue. For example, trekking backpacks may include additional straps that cross the wearer's chest, waist and hips to better distribute the load. Backpacks of intermediate size, for carrying school books, for example, may have additional padding on the shoulder straps to decrease discomfort to the wearer. However, these types of bags may not be suitable or desirable for all applications. For example, a backpack may be oversized or too bulky for a particular application. In these situations, a cinch sack or drawstring backpack may be appropriate, but these backpacks do not typically include comfort features. In particular, a cinch sack or drawstring backpack may be uncomfortable to the wearer if significant weight is carried in the bag.
In view of the foregoing, it is desirable to provide an improved cinch sack backpack that causes less discomfort to a wearer when carrying heavier loads over longer periods of time. It would be advantageous if this backpack could include features which allow the cinch sack backpack to retain the desired simplicity for applications requiring a cinch sack backpack while improving the comfort of the user. A backpack including such features may increase the application of cinch sack backpacks as the comfort of the user carrying heavier loads over longer periods of time increases.